1. Technical Field
The present invention is a tool which compares two hierarchical data structures and produces a third hierarchical data structure indicating the differences between the two input data structures. The user may then traverse the third data structure and select the nodes of interest to create a new fourth data structure comprising components selected from the first and second data structures, based upon the differences highlighted in the third data structure. The preferred embodiment of the present invention provides this facility for XML files.
2. Prior Art
Data is often modeled using structures based upon hierarchy. For example, an XML (Extensible Markup Language) document has a tree hierarchy with the nodes being the element tags in the document. When changes are made between versions of an XML document, one may want to understand what the changes were. Also, in a multi-user environment, it is desirable to be able to merge multiple changes to a single document in a controlled manner.
Current tools which provide difference comparisons between files at the source level (e.g. UNIX diff) do not recognize the context of a hierarchy. Typically, they simply match strings within flat ASCII files.
Thus, there is a need for a software tool that will compare differences between hierarchical structures and provide the user with the ability to reconcile and understand the differences, and select which differences should be merged into the controlled base set of documents.